A fuel dispenser seal is known from the German utility model publication G 87 10859.3. The external diameter of the dispenser is significantly larger than the internal diameter of the orifice of the inlet. Hence, an installation through the orifice is not possible. This configuration rather requires that the fuel dispenser seal be inserted into the inlet from direction of the fuel tank, hence, it must be included in the manufacturing process of the inlet. This is not satisfactory insofar as the fuel dispenser seals which are being discussed here are only used in vehicles which are provided with a catalyzer engine. The use of such seals is dispensable in vehicles which are provided with a conventional combustion engine. Automobile manufacturers offering vehicles which are provided with a catalyzer as well as vehicles having a conventional engine are forced to have a supply of and to install two different embodiments of fuel tanks. The labor and costs involved are significant.
It is an object of the invention to create a fuel dispenser seal which permits supplementary installation of the seal without any problems whenever it is required.
In the fuel dispenser seal in accordance with the invention, the sealing ring is included in a supporting body of a basically tube-like configuration; the supporting body is at least in a partial section elastically configured and a reversible diameter reduction permits introducing the aforesaid body through the orifice into the inlet. The supporting body engages with the inlet via at least one projection facing in a radial direction towards the interior and can be made stationary in an axial direction. Consequently, the fuel dispenser seal in accordance with the invention can be installed subsequently to the manufacture of the fuel tank through the orifice of the inlet; making the supporting body stationary on a projection of the inlet facing in a radial direction towards the interior ensures an immovable, axial fixation in the inlet. This completely meets the present safety requirements and a standardized fuel tank can be used in any case.
The support body can be bipartite and include a flexible external ring which surrounds an internal ring made of an inflexible material. The internal ring has a smaller diameter than the orifice and the internal ring can be axially immovably attached to the external ring. In such a case, the external ring can be made of soft rubber and the internal ring of sheet metal or a hard plastic. This ensures on one hand a good sealing effect of the support body with respect to the inside wall of the inlet and, on the other hand, a good resistance of the support body with regard to the wear resulting from the contact with the fuel dispenser itself. Further, if necessary, it is also possible to produce an external ring from a soft rubber which swells when exposed to fuel. In this case, during use of the fuel dispenser in accordance with the invention, there is a stronger contact pressure of the external ring with the inflexible boundary surfaces surrounding each other in a radial direction on one side of the inlet and on the other side of the internal ring which strongly improves the sealing effect achieved. This is a great advantage, especially in cases where the boundary surfaces have certain surface irregularities which occur during manufacture, for example surface striae.
The external ring can be provided with a support surface facing the orifice. The support surface contacts the internal ring if the internal ring rises above the external ring with a hollow-conically-shaped connecting piece directed toward the orifice and if the connecting piece is provided with at least one longitudinally extending opening and can be engaged behind the part narrowing the orifice of the inlet. The internal ring is thus immovably attached in axial direction between the support surface of the external ring and the part narrowing the orifice of the inlet. Relative dislocations are thus completely excluded.
In such an embodiment, it is advantageous that the support surface be provided with an internal diameter extended in direction to the orifice of the inlet. Only in this case, there is a stress component directed radially towards the exterior during a radial contact pressure of the internal ring which ensures a firm contact of the external ring with the inside wall of the inlet and, as a consequence thereof, a particularly good axial attaching.
The projection of the inlet pointing towards the interior which firmly fixes the support body in axial direction can be configured annularly closed and, for example, can have the shape of a bead. As compared to this, it is less expensive to install an embodiment in which the projection is formed by at least two indentations uniformly distributed in circumferential direction which, for example, can have a calotte-like shape. The appertaining external ring of the fuel dispenser seal is on its external side advantageously provided with a surrounding groove in which the indentations can engage during installation.
The internal ring can be bipartite, including a seal holder and a closing link. The seal holder surrounds the sealing ring with an angular profile on the side of the fuel tank and facing radially towards the exterior and surrounds the closing link on the side facing towards the orifice; the seal holder and the closing link can immovably be connected to each other. The seal holder and the closing link thus form together a groove open to the inside in which the sealing ring can engage. The latter can, for example, have the shape of a conventional groove ring including a sealing lip axially projecting towards the fuel tank. After a possible wear has occurred, it can thus be more easily replaced.
The closing link can be made of a rigid material and have an internal diameter which is hollow-conically extending from the sealing in a direction towards the orifice. The smallest value of the internal diameter is basically identical with the internal diameter of the sealing ring in the section of the end facing the orifice. The sealing ring usually made of soft-elastic rubber is thus well protected against mechanical effects of the fuel dispenser while the latter is inserted or removed.
The closing link can be tube-like configured and snap in an undercut of the seal holder. In addition to the inexpensive manufacture, it can be more easily inserted and fits firmly.
The closing link can be provided with at least one axially projecting flexible tongue; the tongue can be firmly attached to the closing link by snapping into the undercut of the seal holder. Several flexible tongues are advantageously distributed in circumferential direction and each is provided with an aperture to axially hold a clamping device; the flexible tongues can be released from the undercuts of the seal holder by means of the clamping device. Replacing the seal which is possibly required is furthermore made easier. It is advantageous that the flexible tongues axially extend in direction towards the fuel tank. In such a configuration, they cannot interfere with the insertion and removal of the fuel dispenser.